The use of simulated physiological structures for training medical students and for providing skill training to practicing physicians is widespread. Although cadavers have traditionally been beneficially employed for this purpose, cadavers are not always readily available and are not well suited for all types of training.
Simulated physiological structures should preferably be usable repeatedly and should provide a realistic training experience corresponding to what the trainee would experience if performing a procedure on an actual patient. The need for such simulators is significant, because they can provide valuable training that will lead to more effective treatment of patients. For example, medical personnel who administer emergency trauma care can greatly benefit from the training achieved using a simulated physiological structure. Training in administering trauma surgical procedures, which include those procedures that are usually performed on a person who has experienced some form of severe and, often, life-threatening injury, is particularly beneficial. Such procedures may aid in the diagnosis of a condition, or may provide immediate life-saving care until more complete medical treatment is available. The procedures might include clearing a blocked airway or draining accumulations of fluids from internal organs. While appearing to be relatively simple, if these procedures are performed improperly, the result can worsen a patient's condition, placing the patient at an even greater peril of death. By their nature, trauma procedures are usually performed under emergency conditions in which the person administering the care is under time-related stress. It is therefore useful to provide training methods and apparatus to fully prepare students and physicians in these procedures, so that the procedures can be performed properly, without delay, and under stressful conditions.
The use of a training model (such as a cadaver, an animal, or a simulator) is desirable to properly prepare a student or physician to perform procedures on a variety of patients. While anatomy follows general rules, variations based on sex, age, height, and weight are the norm. A surgical student should not just blindly follow directions such as “make an incision four inches long and two inches deep, starting at the navel.” Normal variations, such as the amount of body fat on a specific patient, will significantly change the depth of fat tissue that must be incised to reach an internal organ. Surgeons must rely on their knowledge of general anatomy, and evident cues (e.g., visually noting whether the patient has a low or high percentage of body fat, or whether the patient is a child, an adult, a female, etc.) to determine the correct location and other variable parameters, before performing a procedure on a specific patient. The use of cadavers, animal models, and anatomically correct simulators enable surgical students and physicians to apply their knowledge of anatomy to develop experience in assessing these factors, so as to properly determine the proper parameters to be applied when executing a procedure on a live patient.
To provide the desired level of realism, a simulated physiological structure used for training medical personnel should both tactilely and visually resemble the anatomical structure being simulated. Some prior art medical models achieve part of this goal by being visually very realistic, but are formed of rigid plastic materials that have been painted to achieve a very realistic visual representation of a physiological structure. FIG. 1 schematically illustrates one such prior art model, which visually represents a female torso, including portions of the female reproductive system. A model 10 corresponds to a cut-away section of a female abdomen and includes a womb 11. A baby 12 rests in womb 11, and baby 12 can be removed to enable womb 11 to be more clearly inspected. Model 10 (and baby 12) are implemented using a generally flesh-tone colored hard plastic material. Anatomical details 16 and 18 of the cut away torso are painted onto the hard plastic, to achieve a very visually realistic model. Anatomical details, such as hair 14, are also painted onto baby 12. Model 10 is visually very realistic; however, the hard plastic material is not tactilely realistic.
Prior art human anatomical models have also been developed that employ elastomeric compositions for simulating human tissue. The elastomeric compositions can provide very realistic tactile sensations when incised and handled by a student. However, while elastomeric compositions can be colored to resemble human tissue, the subtle gradations in color present in actual human tissue have heretofore been difficult to reproduce using elastomers. Colored elastomers tend to exhibit uniform shading, whereas actual tissue exhibits significant color variations. Clearly, it would be desirable to provide a simulated physiological structure that is able to provide both more realistic tactile and visual queues to a student who is performing a simulated procedure.